Plasma [Ca++] is regulated by PTH and calcitriol. Calcitonin is not a major regulatory hormone in humans. Ca++ excretion by the kidneys is regulated by PTH, plasma [Ca++], and calcitriol and is altered by changes in acid-base status, ECFV, and plasma Pi.
5.
Ca++ reabsorption by the TAL and distal tubule are regulated by PTH and calcitriol, both of which stimulate Ca++ reabsorption, and by plasma [Ca++].
6.
Plasma [Pi] is regulated by PTH, FGF-23, and calcitriol. Pi excretion is regulated by PTH, FGF-23, dietary phosphate, and growth hormone and is  altered by acid base balance, ECFV expansion,  and glucocorticoids. Bone tumors secrete FGF-23, which enhances renal Pi excretion and thereby causes hypophosphatemia, hyperphosphatemia,  and a defect in bone mineralization (i.e.,  osteomalacia).
Biber J, et al. Phosphate transporters and their function. Annu Rev Physiol. 2013;75:535-550. Christov M, Juppner H. Insights from genetic disorders of phosphate homeostasis. Semin Nephrol. 2013;33:143-157.
Miller T. Control of renal calcium, phosphate, electrolyte, and water excretion by the calcium-sensing receptor. Best Pract Res Clin Endocrinol Metab. 2013;27:345-358.
Palmer BF. Regulation of potassium homeostasis. Clin J Am Soc Nephrol. 2015;10:1050-1060.
Patel A. The primary cilium calcium channels and their role in flow sensing. Pflugers Arch. 2015;467:157-165.
Pearce D, et al. Collecting duct principal cell transport processes and their regulation. Clin J Am Soc Nephrol. 2015;10:135-146.
Bernardo JF, Friedman PA. Renal calcium metabolism. In. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney:
CHAPTER 36 Potassium, Calcium, and Phosphate Homeostasis
Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2225.
Berndt TJ, Kumar R. Clinical disturbances of phosphate homeostasis. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2369.
Malnic G, et al. Regulation of K+ excretion. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:1659.
Murer H, et al. Proximal tubular handling of phosphate. In: Alpern RJ, et al., eds. Seldin and Giebisch’s The Kidney: Physiology and Pathophysiology. 5th ed. Waltham, MA: Elsevier; 2013:2351.
Smogorzewski MJ, et al. Disorders of calcium, magnesium, and phosphate balance. In: Taal MW, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia: Saunders; 2012:689.